Memory architecture and decoder addressing

ABSTRACT

A memory architecture includes a matrixed arrangement of memory cell arrays having interstitial separations bounding each memory cell array. The interstitial separations between memory cell arrays include longitudinal streets, carrying row decoders, and latitudinal streets, carrying column decoders that include sense amplifiers. Decoder control circuits are disposed in the intersections of the longitudinal and latitudinal streets. Each decoder control circuit includes drivers for providing addressing or other signals to pairs of adjacent row or column decoders. Each driver provides a signal to more than one decoder, such as to each of the row or column decoders between which the decoder control circuit is interposed. The decoder control circuit requires fewer drivers, which can be staggered or laterally offset to better accommodate magnitude reductions of the interstitial separations between memory cell arrays, thereby increasing storage density.

This application is a continuation of U.S. Ser. No. 08/874,241, filedJun. 13, 1997 now U.S. Pat. No. 5,892,703.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to integrated circuit memoryarchitectures and more particularly to addressing of decoders containedtherein.

BACKGROUND OF THE INVENTION

Integrated circuit memories that are used for electronic data storageinclude dynamic random access memories (DRAMs), static random accessmemories (SRAMs), electrically erasable and programmable read onlymemories (EEPROMs), synchronous random access memories or other types ofmemories that include a matrix of selectively addressable memory cells.

For example, FIG. 1 is a floorplan block diagram that illustrates thearchitecture of a conventional DRAM 100, which typically includes amatrixed arrangement of multiple memory cell arrays 105, each of whichis understood to contain a matrixed arrangement of memory cells. Theinterstitial separations between the memory cell arrays 105 carrysupport circuits for addressing the memory cells in the memory cellarrays 105, such as for performing reading and writing operations. Theinterstitial separations include longitudinal streets 110 andlatitudinal streets 115.

Longitudinal streets 110 typically include column decoder and senseamplifier circuits, which together are adjacent to or interposed betweenones of memory cell arrays 105. The column decoder and sense amplifiercircuits are used for reading data from and writing data to selecteddigit lines, which are in the memory cell arrays 105 and are coupled tomemory cells therein. Latitudinal streets 115 typically include rowdecoders that are adjacent to or interposed between ones of memory cellarrays 105. The row decoder circuits are used for selectively activatingword lines in a memory cell array 105 for accessing memory cellstherein.

The column decoder and sense amplifier circuits in the longitudinalstreets 110 and the row decoder circuits in the latitudinal streets 115are sometimes referred to collectively as "pitch cell" circuits, becausesuch circuits are laid out on the same pitch (spacing between adjacentones) of the digit lines and word lines to which they are respectivelycoupled. The interstitial separations between memory cell arrays 105occupy a considerable portion of the integrated circuit DRAM. In orderto improve storage density, for reducing the component size ofintegrated circuit DRAM 100 or for increasing the data storagecapability of integrated circuit DRAM 100, the magnitude of theinterstitial separations between memory cell arrays 105 should bedecreased, such as by electrical circuit design or physical layoutdesign techniques. For example, it is known in the art to provide anoutput driver in a row decoder that is interposed between two memorycell arrays 105, where an output node of the output driver provides anoutput signal to a word line in each of the memory cell arrays 105between which the row decoder is interposed. This reduces the size ofthe row decoder and the magnitude of the interstitial separationsbetween memory cell arrays.

However, even if such design techniques are successful, there is a needin the art to provide, in a spatially efficient manner, control signals(e.g., addressing signals) to the row decoders in the latitudinalstreets 115 and to the column decoders in the longitudinal streets 110.Thus, in order to fully realize the gains in storage density arisingfrom reducing the magnitude of the interstitial separations betweenmemory cell arrays 105, there is a need in the art to accommodate suchmagnitude reductions when providing signals to the pitch cells carriedwithin the interstitial separations.

SUMMARY OF THE INVENTION

The present invention allows better utilization of the gains in storagedensity realized by reducing the magnitude of the interstitialseparations between memory cell arrays in an integrated circuit memory.According to one aspect of the invention, such magnitude reductions areaccommodated when providing signals to the pitch cells carried withinthe interstitial separations. In one embodiment, the invention providesan integrated circuit memory having a plurality of memory cell arraysarranged in a grid pattern. Adjacent ones of the memory cell arrays arelaterally separated, thereby defining longitudinal streets. Adjacentones of the memory arrays are vertically separated, thereby defininglatitudinal streets. Gap regions are defined by intersections of thelongitudinal and latitudinal streets. First and second decoders arelocated in the latitudinal streets and separated by the gap region. Adecoder control circuit is located in the gap region and coupled toprovide an output signal to the first and second decoders.

In another embodiment, the invention provides an integrated circuitmemory having a plurality of memory cell arrays arranged in a gridpattern. Adjacent ones of the memory cell arrays are laterallyseparated, thereby defining longitudinal streets. Adjacent ones of thememory arrays are vertically separated, thereby defining latitudinalstreets. A gap region is defined by an intersection of the longitudinaland latitudinal streets. A pair of row decoders is provided. The pair ofrow decoders is located in a latitudinal street. A first row decoder inthe pair has X/2 inputs and is located on a first side of the gapregion. A second row decoder in the pair has X/2 inputs and is locatedon an opposite side of the gap region. Together, the first and secondrow decoders have X inputs. A decoder control circuit is located in thegap region. The decoder control circuit provides X/2 output signals(e.g., shared pairwise) to the X inputs of the first and second rowdecoders.

In another embodiment, the invention provides an integrated circuitmemory having a plurality of memory cell arrays. The memory cell arraysare arranged in a matrix with longitudinal and latitudinal streetsbounding the memory cell arrays. A plurality of row decoders are placedin (and define a magnitude of) the latitudinal streets. Each row decoderis coupled to at least one of the memory cell arrays by a plurality ofword lines. A plurality of sense amplifiers is placed in thelongitudinal streets. Each sense amplifier is coupled to at least one ofthe memory cell arrays by at least one digit line pair. A plurality ofcolumn decoders is placed in the longitudinal streets and, together withthe sense amplifiers, define a magnitude thereof. Each column decoder iscoupled to at least one of the memory cell arrays by a plurality ofdigit lines. A plurality of decoder control circuits are included. Eachdecoder control circuit is placed in an intersection of one of thelongitudinal streets and one of the latitudinal streets. Each decodercontrol circuit carries a plurality of drivers. Ones of the plurality ofdrivers are coupled to more than one row decoder for providing anaddress signal to the more than one row decoder.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like numerals describe substantially similar componentsthroughout the several views.

FIG. 1 is a floorplan block diagram that illustrates the architecture ofa conventional dynamic random access memory (DRAM).

FIG. 2 is a floorplan block diagram that illustrates generally thearchitecture of one embodiment of a memory according to the teachings ofthe present invention.

FIG. 3A is a schematic/floorplan diagram that illustrates generally aportion of a typical decoder control circuit.

FIG. 3B is a schematic/floorplan diagram that illustrates generally aportion of one embodiment of a decoder control circuit according to theteachings of the present invention.

FIG. 4 is a schematic/floorplan diagram that illustrates generally aportion of one embodiment of decoder control circuit according to theteachings of the present invention, rotated from the illustration ofFIG. 3B.

FIG. 5 is a schematic diagram that illustrates generally, by way ofexample, one embodiment of a driver circuit according to the teachingsof the present invention.

FIG. 6 is a schematic/floorplan diagram, similar to the schematicdiagram of FIG. 3B, that illustrates generally a further embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof, and in which is shown byway of illustration specific embodiments in which the invention may bepracticed. These embodiments are described in sufficient detail toenable those skilled in the art to practice the invention, and it is tobe understood that the embodiments may be combined, or that otherembodiments may be utilized and that structural, logical and electricalchanges may be made without departing from the scope of the presentinvention. The following detailed description is, therefore, not to betaken in a limiting sense, and the scope of the present invention isdefined by the appended claims and their equivalents.

The memory architecture of the present invention provides signals tocircuits disposed in interstitial separations between memory cellarrays, while accommodating the reductions in the magnitude of suchseparations that are needed for improving storage densities. FIG. 2 is afloorplan block diagram that illustrates generally the architecture ofone embodiment of a memory 200, such as a dynamic random access memory(DRAM) or other memory, according to the teachings of the presentinvention. Memory 200 typically includes a matrixed grid arrangement ofmultiple memory cell arrays 205, each of which is understood to containa matrixed grid arrangement of memory cells. Each memory cell comprisesa storage capacitor for storing a data bit as a charge and an accesstransistor for accessing the charge.

The interstitial separations between the memory cell arrays 205 includesupport circuits for addressing the memory cells in the memory cellarrays 205, such as for performing reading and writing operations. Theinterstitial separations include longitudinal streets 210 andlatitudinal streets 215. Longitudinal streets 210 are defined by lateralseparations between adjacent memory cell arrays 205. Latitudinal streets215 are defined by vertical separations between adjacent memory cellarrays 205. Longitudinal streets 210 typically include column decoders220, which typically also include sense amplifier circuits. Columndecoders 220 are adjacent to or interposed between ones of memory cellarrays 205. Column decoders 220 are used for reading data from andwriting data to selected digit lines in one or more adjacent memory cellarrays 205 and coupled to memory cells therein. Latitudinal streets 215typically include row decoders 225 that are adjacent to or interposedbetween ones of memory cell arrays 205. The row decoders 225 are usedfor selectively activating word lines in one or more adjacent memorycell arrays 205 for accessing memory cells therein. Decoder controlcircuits 230 are disposed in gap regions defined by the intersections oflongitudinal streets 210 and latitudinal streets 215 for providingsignals, such addressing or other control signals, to ones of the rowdecoders 225 or to ones of column decoders 220 (including providingcontrol signals to sense amplifiers in the column decoders 220).

The column decoders 220 in longitudinal streets 210 and the row decoders225 in latitudinal streets 215 are sometimes referred to collectively as"pitch cell" circuits, as described above. Shrinking the size of columndecoders 220 and row decoders 225 reduces the magnitude of theinterstitial separations between memory cell arrays 205, therebyincreasing storage density. However, decoder control circuits 230 mustalso be designed to accommodate the reduced-magnitude interstitialseparations, since they are disposed in the intersections oflongitudinal streets 210 and latitudinal streets 215.

As described in detail below, one embodiment of the present inventionprovides a matrixed arrangement of memory cell arrays 205, a number ofgap regions defined by the intersections of longitudinal streets 210 andlatitudinal streets 215. Also provided are pairs of decoders, such asrow decoders 225, each pair of row decoders 225 located in a latitudinalstreet. A first row decoder in the pair is located on a first side of agap region, and a second row decoder in the pair is located on anopposite side of the gap region. Decoder control circuits 230 areprovided, each located in a gap region defined by the intersections oflongitudinal streets 210 and latitudinal streets 215. The decodercontrol circuit 230 provides output signals to one of the pairs of rowdecoders 225.

FIG. 3A is a schematic/floorplan diagram that illustrates generally aportion of a typical decoder control circuit 229, interposed between apair of decoder circuits such as first and second row decoder circuits225A-B to which it provides signals. Decoder control circuit 229receives input signals, such as decoder addressing signals, at inputnodes 300A-N, such as via interconnection lines carried in theinterstitial separations, e.g. in longitudinal streets 210 orlatitudinal streets 215. Decoder control circuit 229 includes drivers304A-N, each receiving one of the input signals at input nodes 300A-N,and providing, in response thereto, a resulting output signal at one ofoutput nodes 309A-N to one of row decoders 225A or 225B. Thus, decodercontrol circuit 229 uses X individual drivers 304A-N to individuallyprovide a total of X output signals to X inputs of row decoders 225A-B,which include the X/2 inputs of row decoder 225A and the X/2 inputs ofrow decoder 225B.

FIG. 3B is a schematic/floorplan diagram that illustrates generally aportion of one embodiment of decoder control circuit 230, according tothe teachings of the present invention, interposed between a pair ofdecoder circuits such as first and second row decoder circuits 225A-B towhich it provides signals. Decoder control circuit 230 receives inputsignals, such as decoder addressing signals, at input nodes 300A-N, suchas via interconnection lines carried in the interstitial separations,e.g. in longitudinal streets 210 or latitudinal streets 215. Decodercontrol circuit 230 includes drivers 305A-N, each receiving one of theinput signals at input nodes 300A-N, and providing, in response thereto,a resulting output signal at one of output nodes 310A-N to both of rowdecoders 225A and 225B.

Decoder control circuit 230 uses shared drivers 305A-N, each of whichprovides signals in opposite directions to row decoders 225A-B locatedon opposite sides of the gap region in which the decoder control circuit230 is disposed, rather than using separate ones of drivers 305A-N forindividually providing resulting output signals to each of row decoders225A and 225B. For example, in one embodiment, a polysilicon feedthroughinterconnection can be used to route the signal at one of the outputnodes 310A-N to one or more of row decoders 225A and 225B. Thus, decodercontrol circuit 230 uses X/2 shared drivers 305A-N to provide a total ofX/2 output signals to the X inputs of row decoders 225A-B. The X/2output signals provided by decoder control circuit 230 are sharedbetween the X/2 inputs of row decoder 225A and the X/2 inputs of rowdecoder 225B. Since fewer drivers are used in decoder control circuit230 than in decoder control circuit 229, the vertical dimension ofdecoder control circuit 230 can be less than that of decoder controlcircuit 229. As a result, decoder control circuit 230 more easilyaccommodates magnitude reductions of the interstitial separationsbetween memory cells 105, thereby improving memory storage density.

In one embodiment, the input signals at input nodes 300A-N includeaddressing signals, for which resulting output signals are provided atnodes 310A-N to row decoders 225A-B for addressing particular word linesin one or more memory cell arrays 205 that are adjacent to the rowdecoders 225A-B. However, the input signals could also include othercontrol signals for which corresponding resulting signals are providedto row decoders 225A-B. Embodiments of drivers 305A-N include inverters,buffers, logic circuits, latches, flip-flops, or other circuits havingsufficient transconductance capabilities to drive output nodes 310A-Nand the corresponding capacitive loads in each of row decoders 225A and225B.

FIG. 4 is a schematic/floorplan diagram that illustrates generally aportion of one embodiment of decoder control circuit 230, according tothe teachings of the present invention, rotated from the view shown bythe illustration of FIG. 3B, i.e. having decoder control circuit 230interposed between column decoder circuits 220A-B to which it providessignals. In this embodiment, decoder control circuit 230 receives inputsignals at input nodes 400A-N, such as via interconnection lines carriedin interstitial separations, e.g. in longitudinal streets 210 orlatitudinal streets 215.

Decoder control circuit 230 includes drivers 305A-N, each receiving oneof the input signals at input nodes 400A-N, and providing, in responsethereto, a resulting output signal at one of output nodes 410A-N to bothof column decoders 220A and 220B, rather than using separate ones ofdrivers 305A-N for individually providing resulting output signals toeach of column decoders 220A and 220B. In one embodiment, the outputsignals that are provided to column decoders 220A-B are addressingsignals for controlling the accessing of particular digit lines in oneor more adjacent memory cell arrays 205. In another embodiment, theoutput signals that are provided to column decoders 220A-B includecontrol signals for sense amplifiers contained therein. It is understoodthat the embodiments of FIGS. 3B and 4 could also be combined, such asto provide signals to pairs of row decoders 225 and pairs of columndecoders 220, each of which the decoder control circuit 230 isinterposed between.

FIG. 5 is a schematic diagram that illustrates generally, by way ofexample, one embodiment of a driver 305 such as driver 305A, asdescribed with respect to FIG. 3B. In FIG. 5, driver 305A includes latch500 coupled to input node 300A, such as through n-channel field-effecttransistor (NFET) pass switch 505, for receiving an input signal, andproviding an output signal at node 310A in response thereto. Pass switch505 also receives control signal at node 510 for coupling/isolating theinput signal at node 300A from the input node 515 of latch 500. Driver305A also includes a reset switch 520, such as a p-channel field-effecttransistor (PFET), which is controlled by a reset signal received atnode 525, for coupling/isolating the input node 515 of latch 500 to andfrom an appropriate voltage level, such as a positive power supplyvoltage V_(CC). Latch 500 includes back-to-back inverters 530 and 535.Feedforward inverter 530 provides the output signal at node 310A, e.g.to capacitive loads in each of row decoders 225A and 225B, and thepullup and pulldown transistors therein must therefore be scaledappropriately to provide sufficient transconductance capability for thispurpose.

FIG. 6 is a schematic/floorplan diagram, similar to the schematicdiagram of FIG. 3B, that illustrates generally a further embodiment ofthe present invention. In FIG. 6, drivers 305A-N are configured in astaggered arrangement, in which the drivers are arranged in pairs (e.g.,305A-B). Each driver 305 in the pair is laterally offset from the otherdriver 305 in the pair, in order to better accommodate any reduction ofthe height of the latitudinal streets 215 between memory cell arrays205. In FIG. 6, the lateral offset is illustrated by approximatelyvertically aligned drivers 305 in each pair of drivers, but it isunderstood that the drivers 305 in each pair need not be exactlyvertically aligned. The drivers 305 in each pair may be verticallyoffset as well as laterally offset in accordance with one aspect of thepresent invention. It is also understood that the pairwise arrangementof drivers 305 in FIG. 6 could be analogously applied to the schematicdiagram of FIG. 4 to provide signals to column decoders 220 rather thanrow decoders 225.

By using a single shared driver 305 to provide an output signal to eachone of a pair of row decoders 225 or a pair of column decoders 220, thedecoder control circuit 230 can be physically implemented in less spacethan if a first driver was used to provide an output signal to a firstrow or column decoder and a second driver was used to provide an outputsignal to a second row or column decoder. Thus, the memory architectureof the present invention better accommodates the magnitude reductions ofthe longitudinal streets 210 or latitudinal streets 215. One aspect ofthe present invention is that the sharing of drivers described aboveallows decoder control circuit 230 to avoid limiting the magnitude ofthe interstitial separations between memory cell arrays 205. Themagnitude of the interstitial separations is limited only by the pitchcells, i.e. row decoders 225 and column decoders 220. Thus, themagnitude reductions of the interstitial separations, together with thecorresponding size reduction of decoder control circuit 230, increasethe memory storage density.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Many other embodiments will beapparent to those of skill in the art upon reviewing the abovedescription. The scope of the invention should, therefore, be determinedwith reference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

What is claimed is:
 1. An integrated circuit memory, comprising:firstand second decoders separated by a first gap region; and a decodercontrol circuit located in the first gap region, the decoder controlcircuit including a driver that is coupled to provide at least oneoutput signal to each of the first and second decoders.
 2. The memory ofclaim 1, in which the first and second decoders are row decoders.
 3. Thememory of claim 1, in which the first and second decoders are located inlatitudinal streets.
 4. The memory of claim 1, in which the first andsecond decoders are column decoders.
 5. The memory of claim 1, in whichthe first and second decoders are located in longitudinal streets. 6.The memory of claim 1, in which the driver includes an inverter.
 7. Thememory of claim 1, in which the driver includes a latch.
 8. Anintegrated circuit memory, comprising:a plurality of memory cell arraysarranged in a grid pattern, adjacent ones of the memory cell arraysbeing laterally separated, thereby defining longitudinal streets, andadjacent ones of the memory arrays being longitudinally separated,thereby defining latitudinal streets; gap regions including a first gapregion, each defined by an intersection of the longitudinal andlatitudinal streets; first and second row decoders located in thelatitudinal streets and separated by the first gap region; and a decodercontrol circuit located in the first gap region and coupled to providean address signal to the first and second decoders, the decoder controlcircuit including a driver selected from the group consisting of aninverter and a latch.
 9. An integrated circuit memory, comprising:firstand second decoders, each having X/2 inputs and together having Xinputs; a first gap region between the first and second decoders; and adecoder control circuit located in the first gap region and includingX/2 drivers providing X/2 output signals to the X inputs of the firstand second decoders.
 10. The memory of claim 9, wherein each driver inthe decoder control circuit provides an output signal to an input of thefirst decoder and to an input of the second decoder.
 11. The memory ofclaim 9, wherein the driver includes an inverter.
 12. The memory ofclaim 9, wherein the driver includes a latch.
 13. The memory of claim 9,wherein the drivers are arranged in a staggered configuration, such thatthe X/2 staggered drivers are arranged in X/2 lateral rows.
 14. Thememory of claim 9, wherein the drivers are arranged in pairs, eachdriver in the pair laterally offset from the other driver in the pair,such that the X/2 staggered drivers are arranged in X/4 lateral rows.15. An integrated circuit memory, comprising:a plurality of memory cellarrays arranged in a grid pattern, adjacent ones of the memory cellarrays being laterally separated, thereby defining longitudinal streets,and adjacent ones of the memory arrays being longitudinally separated,thereby defining latitudinal streets; a gap region, defined by anintersection of the longitudinal and latitudinal streets; a pair of rowdecoders located in a latitudinal street, a first row decoder of thepair located on a first side of the gap region, and a second row decoderof the pair located on an opposite side of the gap region, and the firstand second row decoders each having X/2 inputs and together having Xinputs; and a decoder control circuit located in the first gap regionand including X/2 drivers providing X/2 output signals to the X inputsof the first and second row decoders, wherein each driver provides anoutput signal to an input of the first row decoder and to an input ofthe second row decoder, and each driver is selected from the groupconsisting of an inverter and a latch.
 16. The memory of claim 15,wherein the drivers are arranged in a staggered configuration, such thatthe X/2 staggered drivers are arranged in X/2 lateral rows.
 17. Thememory of claim 15, wherein the drivers are arranged in pairs, eachdriver in the pair laterally offset from the other driver in the pair,such that the X/2 staggered drivers are arranged in X/4 lateral rows.18. An integrated circuit memory, comprising:a plurality of rowdecoders; and a plurality of drivers, each driver coupled to more thanone row decoder for providing an address signal to the more than one rowdecoder, each driver interposed between a pair of the row decoders. 19.An integrated circuit memory, comprising:a plurality of memory cellarrays, arranged in a matrix with longitudinal and latitudinal streetsbounding the memory cell arrays; a plurality of row decoders, placed inthe latitudinal streets and defining a magnitude thereof, each rowdecoder coupled to at least one of the memory cell arrays by a pluralityof word lines, each row decoder including X/2 inputs such that each pairof row decoders includes X inputs; a plurality of sense amplifiers,placed in the longitudinal streets, each sense amplifier coupled to atleast one of the memory cell arrays by at least one digit line; aplurality of column decoders, placed in the longitudinal streets and,together with the sense amplifiers, defining a magnitude thereof, eachcolumn decoder coupled to at least one of the memory cell arrays by aplurality of digit lines; and a plurality of decoder control circuits,each decoder control circuit placed in an intersection of one of thelongitudinal streets and one of the latitudinal streets, and carrying aplurality of drivers, ones of the drivers coupled to more than one rowdecoder for providing an address signal to the more than one rowdecoder, such that the decoder control circuit provides X/2 outputsignals to the X inputs of a pair of row decoders.
 20. An integratedcircuit memory, comprising:first and second decoders separated by afirst gap region; and means for performing the function of controllingand addressing both of the first and second decoders, said means beinglocated in the first gap region between the first and second decoders.